1. Field of Disclosure
The present disclosure of invention relates to a backlight unit and a display apparatus having the same. More particularly, the present disclosure relates to a backlight unit capable of operating with controlled or reduced power consumption and a display apparatus having such a low power backlight unit.
2. Description of Related Technology
In general, a conventional liquid crystal display (LCD) includes a set of liquid crystal display panels or substrates having liquid crystal material interposed between them and defining a plurality of electronically controllable light shutters which can be selectively actuated so as to display desired black and white or colored images. Typically a backlight providing unit is disposed under the liquid crystal display panels to supply backlighting light to the panels for passage through the electronically controllable light shutters defined by the panels.
In a case where light emitting diodes (LED's) are employed as the light sources of the backlight unit, the backlight unit is typically structured to include a plurality of strings of light emitting sources where the strings are connected substantially in parallel and where each string contains a plurality of series connected LED's or other light sources. The backlight unit is typically further structured to include a DC/DC converter that supplies an appropriate range of DC driving voltages to the light source strings, and one or more driver IC's connected to corresponding ones or groups (banks) of the light source strings by a respective plurality of connection channels. However, what constitutes an appropriate range of DC driving voltages may vary with conditions.
Recently, because of growth in size of LCD panels, the number of light source strings that are used has gradually increased. However, because the number of connection channels that are drivable by each given driver IC is limited by its design to a fixed number of channels, the number of the driver IC's that have to employed inside the backlight unit has increased in accordance with the commensurate increase in the number of utilized light source strings. This increase in number of driver ICs creates the problem of how to efficiently regulate the system without substantial increases in size and cost of power control circuits included in the backlight unit.